Writing in the WSJ earlier this week Ed Lu and Martin Rees remind us that our planet is forever traveling through a dangerous neighborhood (not that the people of Chelyabinsk will need reminding of that), and, quite correctly, argue that we should take a few precautions:

…The chance in your lifetime of an even bigger asteroid impact on Earth [than Tunguska in 1908]—with explosive energy of 100 megatons of TNT—is about 1%. Such an impact would deliver many times the explosive energy of all the munitions used in World War II, including the atomic bombs. This risk to humanity is similar to an individual’s odds of dying in a car accident. That risk is small, but would you drive a car without air bags and seat belts? The question is apt because our society is effectively doing so with regard to the risk of a devastating asteroid strike.

NASA has managed to find and track more than 90% of these major asteroids, so a civilization-ending impact in the next 100 years could come only from one of the undiscovered 10% of asteroids larger than 3,000 feet across. But smaller and more numerous asteroids remain a threat simply because we have mapped only a small percentage of them and therefore don’t know if an impact is imminent.

We have the technology to deflect these asteroids—through small spacecraft known as kinetic impactors and gravity tractors that can change an asteroid’s trajectory—but only if we have years of advance warning. We discovered 2012 DA14 only a year ago, so had it been on a collision course with Earth, there is nothing we could have done about it except evacuate the area near the expected impact site and hope for the best.

To defend ourselves, we first have to find and track the asteroids (like 2012 DA14) large enough to do great damage should they strike Earth. There are about one million such asteroids in dangerous orbits near Earth, yet scientists have identified the trajectories of less than 1% of them (fewer than 10,000). For every 2012 DA14 we know of, there are 99 more we know nothing about.

That is why the B612 Foundation was established in 2002 and since 2012 has been building the Sentinel Space Telescope to find threatening asteroids before they find us. It is part of the most ambitious and important private space mission in history. The Sentinel telescope will give humanity decades of warning before a future asteroid impact so we can employ space technology to protect the planet. Because this is a privately financed project, the general public can get involved in making Sentinel a success.

On most days, human civilization wins the game of cosmic roulette. But just as we take precautions to reduce our individual risks of dying in car accidents or earthquakes, we should be doing the same to reduce our societal risk of a catastrophic asteroid impact. Let’s open our eyes and stop gambling with our future….

We waste a fortune on measures (that will have no impact for decades, if ever) to tamper with the climate. Some of that money would be better spent on asteroid insurance.

James Bennett writes that one benefit of better tracking would be the ability “to predict even small events such as yesterday’s at Chelyabinsk, thus preventing missile early-warning systems from confusing them with hostile attacks”. He notes that “Chelyabinsk was a closed city and weapons development site in Soviet days…It is quite possible the relatively unsophisticated Soviet early-warning system might have reported it as a human-caused act.”

And who knows what might then have happened, as Bennett points out, in the tense atmosphere of, say, the late Brezhnev era?

Of course, these days nuclear missiles are only stationed in the calmest, most secure of nations, so there’s no need to worry.